1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to apparatuses and methods for preserving and restoring low roughness on the entire outer surface of a device (e.g., a streamer) used underwater for seismic surveys.
2. Discussion of the Background
Marine seismic surveys are used in the oil and gas industry to map and interpret potential petroleum reservoirs under the seafloor. The size and scale of seismic surveys has increased along with significant concurrent increases in computer power. While 3D seismic surveys are exploratory, 4D surveys are 3D seismic surveys repeated over a period of time to observe reservoir depletion during production and identify areas where there are barriers to flow that may not be easily detectable.
In marine seismic surveys, information is gathered by analyzing reflected and refracted seismic waves, which are detected by seismic receivers such as hydrophones distributed along cables towed by vessels or placed at the ocean bottom. These cables, known as streamers, which are deployed in water for long periods, may be damaged mechanically or due to proliferation of microorganisms (bio-fouling) on their outer surface. Micro-cracks in some areas are particularly dangerous for streamers because barnacles (prevalent in bio-fouling) prefer to attach to patches with higher roughness, which amplifies mechanical damage to the streamer jacket and, in time, renders the streamer unusable.
To diminish bio-fouling, it has been considered manufacturing streamers with a permanent outer layer that has antifouling properties (as disclosed, for example, in U.S. Pat. No. 7,835,222, U.S. Patent Application Publication No. 2010/0020644 and U.S. Patent Application Publication No. 2011/0174207, the contents of which are incorporated herein by reference). However, when the permanent outer layer with antifouling properties is damaged (e.g., mechanically or worn out) and higher roughness patches occur on the streamer's outside surface, bio-fouling increases on these patches and eventually damages the seismic receivers housed inside the streamer. In other words, although the permanent outer layer with antifouling properties may decrease bio-fouling on average, its presence does not preclude or solve the problem of higher roughness patches, and it is not practical to repair or replace this damaged permanent outer layer.
Accordingly, it would be desirable to provide systems and methods that preserve or restore low roughness on the streamer jacket.